1. Field of the Invention
The present invention relates to a venting device for use in an automotive fuel tank and adapted to regulate pressure in the fuel tank.
2. Description of the Related Art
A fuel tank venting device is disclosed for example in JP 2006-44586 A. Specifically, the automotive fuel tank system is furnished with a fuel cutoff valve installed in the upper part of the fuel tank, a canister connected to the fuel cutoff valve via an external passage, and a check valve disposed in the external passage. The fuel cutoff valve is employed as a full fuel control valve designed to close during fueling, or as a rollover valve designed to close when the vehicle tilts; and through rise and fall of a float in accordance with the fuel level in the tank will ensure that vapors are vented to the outside, as well as preventing fuel from spilling out from the fuel tank. The check valve is designed to inhibit fuel which has seeped from the tank into the fuel cutoff valve from flowing into the canister, as well as to open according to tank internal pressure in order to prevent tank internal pressure from rising above a prescribed value and to prevent fuel from being sprayed back out from the inlet pipe during fueling.
However, a problem with the check valve of the conventional fuel tank venting device is that if there is a sudden rise in tank internal pressure, the valve may not be able to respond adequately to prevent fuel from seeping into the canister or to prevent fuel from being sprayed back during fueling.